JP2003293169A - Fluorine resin coated Al material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an Al material for a precoat having excellent weather resistance and antifouling property and excellent workability. SOLUTION: A composite chemical conversion film 2 composed of an Al plate 1, an organic component and an inorganic component formed by coating the surface of the Al plate 1, and a composite chemical conversion film 2 formed by coating the composite chemical conversion film 2. A fluororesin-coated Al material comprising a fluororesin coating 3, wherein the fluororesin coating is a baking coating of a mixture of a solvent-soluble fluororesin and a curing agent.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fluororesin film A
l material, and more specifically, to a fluororesin-coated Al material that exhibits excellent workability, antifouling property, and weather resistance.

[0002]

2. Description of the Related Art Since Al materials are lightweight and have excellent corrosion resistance, they are used as materials for various building materials and civil engineering products. And in the case of outdoor building materials and civil engineering products, since they are actually used in the state of being exposed to the surrounding environment,
The surface of the material is required to have excellent weather resistance and, in recent years, excellent antifouling property against dust, exhaust gas, rain streaks and the like.

Therefore, conventionally, the Al plate has been used in a state in which its surface is coated with various synthetic resins to form a synthetic resin film. Among these synthetic resins, the fluorine-based resin is remarkably excellent in weather resistance as compared with other synthetic resins, and is therefore widely used as a material for the film. In that case, in the field of exterior building materials and civil engineering products such as soundproof walls, Al materials that have not been resin-coated are often used in the past. It is desirable that the formed film be transparent without containing it.

The following prior art is known as an Al material whose film is made of a fluororesin and whose film is transparent. That is, a solvent-soluble fluororesin system obtained by coating the surface of an Al plate to form a phosphoric acid chromate conversion film, and adding a polyfluorinated carbon chain and a hydrophilic polymer on the conversion film. Forming a coating film of paint (see JP-A-1-198653), or
Forming a coating film of a solvent-soluble fluororesin coating material in which a hydrolyzable silane compound is added to a polymer of a hydrocarbon-based vinyl ether having a hydroxyl group and fluorine-containing ethylene (see JP-A-7-82520) It is an Al material having a two-layered surface structure manufactured by.

In the case of these Al materials, the chemical conversion coating contributes to the coating adhesion and corrosion resistance, and the fluororesin coating on the outermost surface is rich in weather resistance and also transparent, so that it has good weather resistance. The material has good antifouling property, and at the same time, it has a metallic feeling similar to that of the conventional Al material. By the way, since building materials and civil engineering products have various shapes suitable for their intended use, when the Al material is used in those fields of application, it is necessary to subject the Al material to predetermined processing. is necessary.

In this case, when the above-mentioned Al material of the prior art, that is, the Al material on which the fluorine resin film is already formed on the outermost surface (the film is pre-coated) is subjected to, for example, bending, At the processed portion, peeling often occurs inside the chemical conversion film or between the chemical conversion film and the fluororesin film. It is considered that this is because the chemical conversion film is a hard inorganic film made of phosphoric acid chromate, and the adhesion between the chemical conversion film and the organic fluororesin film is insufficient.

Such a problem can be solved by processing the Al plate itself into a predetermined shape in advance and then sequentially forming the above-described chemical conversion film and fluorine-based resin film on the surface of the processed product. is there. However, in that case, the manufacturing process of the target Al material becomes long, and the precoat Al
It is economically disadvantageous compared to the case of processing wood. It is an object of the present invention to provide a fluorine-based resin-coated Al material which is excellent not only in weather resistance and antifouling property but also in processability and capable of precoating.

[0008]

In order to achieve the above-mentioned object, in the present invention, a composite type chemical conversion comprising an Al plate and an organic component and an inorganic component formed by coating the surface of the Al plate. A film and a fluorine-based resin film formed by coating the composite chemical conversion film, wherein the fluorine-based resin film is a baked film of a mixture of a solvent-soluble fluorine-based resin and a curing agent. A fluororesin-coated Al material is provided.

Specifically, there is provided a fluororesin-coated Al material in which the organic component is a water-soluble resin and the inorganic component is at least one selected from the group of chromates, Zr compounds and Ti compounds. , More preferably, the composite type chemical conversion coating film is a coating film composed of chromium phosphate and a water-soluble acrylic resin, a coating film composed of titanic acid and a water-soluble phenolic resin,
Alternatively, there is provided a fluororesin-coated Al material which is any one of coating films made of zirconium carbonate and a water-soluble acrylic resin.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 1, an Al material of the present invention is formed by forming an Al plate 1, a composite chemical conversion coating 2 described below for coating the surface thereof, and further coating it. It is composed of a fluorinated resin film 3 described later. The Al plate 1 of this Al material may be made of pure Al, or may be made of various Al alloys.

The chemical conversion film 2 is composed of a composite of an inorganic component and an organic component, and more specifically, is a coating film made of a mixture paint composed of an inorganic component and an organic component described later. This conversion film 2
Has good adhesion to the Al plate 1 which is the same inorganic material due to the function of the contained inorganic component, and at the same time, due to the function of the organic component, is formed on the chemical conversion film 2 and is made of the same organic material. Adhesion with a certain fluorine-based resin film 3 is also good, and as a result, peeling between films during processing of the Al material is suppressed.

[0012] Further, since the chemical conversion film 2 is more flexible by the action of the organic component of the chemical conversion film 2 than the case where only the inorganic component is contained, the stress applied to the chemical conversion film 2 during the processing of the Al material is absorbed. Then, the Al plate 1 and the fluororesin film 3
A buffer function is added between and, so even if it is after processing,
Adhesion between the Al plate 1 and the fluororesin film 3 is secured. As the inorganic component of the chemical conversion film 2, for example, chromate such as chromium phosphate, Zr compound such as zirconium carbonate or zirconium fluoride, or T such as titanic acid.
The i compound can be given as a preferable example.

Examples of the organic component include water-soluble resins such as polyacrylic acid, polyvinyl alcohol, cellulose, ethylene maleic anhydride, polyvinylpyrrolidine, and polyvinyl methyl ether. The chemical conversion film 2 is prepared by mixing the above components with, for example, ion-exchanged water as a diluent to prepare a coating material, and applying the coating material to the surface of the Al plate 1 by, for example, a spray method or a roll coating method, and then, for example, the highest reaching plate. Temperature (hereinafter, PM
It can be formed by drying at 80 to 120 ° C.

When the chromate is used as the inorganic component, the thickness of the chemical conversion coating 2 is such that the Cr deposition amount is 5 to 40 mg /
When the thickness is set to m ² and the Zr compound is used as the inorganic component, the Zr adhesion amount is set to 3 to ²⁰ mg / m ^2, and when the Ti compound is used as the inorganic component, the Ti adhesion is set. It is preferable to set the thickness so that the amount is 3 to 30 mg / m ² . This is because, in any case, good workability of the Al material can be imparted.

The fluororesin film 3 is obtained by mixing a solvent-soluble fluororesin, which is a resin obtained by copolymerizing a copolymerizable monomer such as fluoroolefin and vinyl ether, and a curing agent. Further, an aromatic hydrocarbon solvent, alcohol solvent, ether solvent, ester solvent, ketone solvent or the like is added to the mixture to prepare a paint having a predetermined viscosity, and this paint is applied, for example, to a roll coater, a blade coater, a sprayer. It is formed by applying it on the chemical conversion film 2 by using a device and then baking it at, for example, PMT of 200 to 300 ° C.

Here, as the curing agent, for example, polyisocyanate, one whose isocyanate group is blocked by caplactam, melamine, benzoguanamine, urea or the like can be used. This fluororesin film 3 is
Since a solvent-soluble fluororesin is used as the base material, the crosslink density in the formed film is relatively high, and since the film contains fluorine atoms, it has good antifouling properties by itself. .

However, when a hydrolyzable silane compound such as alkoxysilane is further added during the preparation of the above-mentioned paint, the hydrophilicity of the surface of the formed film 3 is improved, and the stain resistance to rain streaks is also included. Therefore, the antifouling property of the Al material is further improved, which is preferable.

[0018]

[Examples] (1) Manufacture of Al material A degreasing treatment and water washing were sequentially performed on an Al alloy plate (thickness 1.0 mm) of a material specified by JIS A5052, and then A
The following treatments were separately performed on the surface of the 1-alloy plate to obtain 5 types of Al-alloy plates on which a chemical conversion film was formed.

Treatment A: Chromium phosphate and a water-soluble acrylic resin were mixed and further diluted with ion-exchanged water, which was then coated by a roll coater method and baked at PMT of 100 ° C. Treatment B: Titanic acid and a water-soluble phenolic resin were mixed, diluted with ion-exchanged water, applied by a roll coater method, and further baked at PMT of 100 ° C.

Treatment C: Zirconium carbonate and a water-soluble acrylic resin were mixed, further diluted with ion-exchanged water, then applied by a roll coater method, and baked at PMT of 100 ° C. Treatment D: A commercially available drug consisting of phosphoric acid, chromic acid, and hydrofluoric acid (drug name: Alsurf 407/47, manufactured by Nippon Paint Co., Ltd.) was applied by a spray method at a treatment temperature of 45 ° C., followed by washing with water, It was dried and treated with phosphoric acid chromate. Treatment E: A treatment solution of an aqueous solution in which phosphoric acid, titanic acid and hydrofluoric acid were mixed was applied by a spray method at a treatment temperature of 45 ° C., followed by washing with water and drying to perform titanium phosphate treatment.

The following treatment was applied to each of the Al alloy plates on which the chemical conversion coating was formed to form a fluororesin coating, and the Al materials in which the coatings were combined as shown in Table 1 were used. Manufactured. Treatment a: An acrylic dispersion type fluorine-based coating material in which polyvinylidene fluoride (PVDF) was dispersed in an acrylic resin was applied by a roll coater method, and further baked at PMT 245 ° C.

Treatment b: A solvent-soluble fluorine-based coating material in which a fluoroolefin-vinyl ether copolymer (EEVE) and a blocked isocyanate were mixed was applied by a roll coater method, and then baked at PMT of 230 ° C. Treatment c: The treatment liquid used in treatment b and the hydrolyzable silane compound are mixed and applied by a roll coater method, and then PM
It was baked at T230 ° C.

(2) Performance evaluation Weather resistance: A cross-cut (size: 35 mm) was put on the coating surface of each Al alloy material, a Duo cycle test was carried out for 500 hours, and then a tape test was carried out. ○, the case of peeling of the film is evaluated as ×.

Antifouling property: An aqueous solution containing 5% by weight of carbon black was sprayed on the coating surface of each Al alloy material, and then dried at a temperature of 60 ° C. for 1 hour. Then, in running water, the carbon black adhering to the surface of the film was wiped off with gauze, and the antifouling property of the film surface was evaluated according to the following criteria. That is, ∘ when all could be removed cleanly, ∘ when slightly remained but almost cleanly removed, Δ when slightly remained, and x when hardly removed.

Workability: 100 on the coating surface of each Al alloy material
Individual squares (dimensions of one square, 1 mm × 1 mm) were engraved, and an Erichsen test of 5 mm overhang was performed, and then a tape test was performed, and the workability was evaluated according to the following criteria. That is,
When the number of remaining films is 100, it is ○, and the number of remaining films is 5
The case of 1 to 99 is indicated by Δ, and the case of the number of remaining films being 50 or less is indicated by ×.

The above results are collectively shown in Table 1.

[0027]

[Table 1]

The following is clear from Table 1. (1) The Al materials of the examples all have weather resistance, antifouling property,
Excellent workability. In particular, no peeling of the film occurs, the workability is excellent, and it has sufficient practicality as an Al material for precoating.

(2) On the contrary, the Al material of the comparative example is inferior in weather resistance, antifouling property and workability. For example, in the case of Comparative Example 1, since the fluorine-based resin film on the outermost surface is an acrylic dispersion type, both weather resistance and antifouling property are inferior, and the chemical conversion film is an inorganic type film. The sex is also inferior. In Comparative Examples 2 and 3, the fluorine resin film on the outermost surface is of the same type as that of the example, so that the weather resistance and antifouling property are good, but the chemical conversion film is an inorganic film, and the workability is poor. ing.

[0030]

As is clear from the above description, the Al material of the present invention not only has good weather resistance and antifouling property, but also
It has excellent workability and is useful as an Al material for precoating.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of an Al material of the present invention.

[Explanation of symbols]

1 Al material 2 Chemical conversion film 3 Fluorine resin film

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C23C 22/33 C23C 22/33 22/56 22/56 F term (reference) 4D075 AE03 BB26Z BB28Z CA09 CA13 CA32 CA34 DA06 DB07 DC01 DC05 DC10 EA06 EA07 EB07 EB13 EB16 EB19 EB20 EB22 EB32. DA06 DA11 EB11 4K044 AA06 AB02 BA12 BA15 BA17 BA21 BB03 BC02 BC05 CA53 CA62

Claims (4)

[Claims] 1. An Al plate, a composite type chemical conversion film formed of an organic component and an inorganic component formed by coating the surface of the Al plate, and a fluororesin formed by coating the composite type chemical conversion film. A fluororesin-coated Al material comprising a coating film, wherein the fluororesin coating film is a baked coating film of a mixture of a solvent-soluble fluororesin and a curing agent. 2. The fluororesin-coated Al material according to claim 1, wherein the organic component is a water-soluble resin and the inorganic component is at least one selected from the group consisting of chromate, Zr compound, and Ti compound. 3. The composite chemical conversion coating comprises a coating film made of chromium phosphate and a water-soluble acrylic resin, a coating film made of titanic acid and a water-soluble phenolic resin, or a coating film made of zirconium carbonate and a water-soluble acrylic resin. The fluorine-based resin-coated Al material according to claim 1 or 2, which is any one kind. 4. The fluororesin-coated Al material according to claim 1, wherein the mixture further contains a hydrolyzable silane compound.